Technical Abstract:
Appropriate indicators and indices for assessing soil quality on a regional scale are needed. Our objectives were to: 1) identify soil quality factors present at a regional scale, and 2) interpret these factors using an index of the attributes that comprise them. An Ascalon (Fine-loamy, mixed, superactive, mesic Aridic Argiustoll) soil was sampled from a statistically representative subset of National Resource Inventory (NRI) points in the Central High Plains Major Land Resource Area (MLRA) 67 and analyzed for 18 soil attributes. Factor analysis was used to group correlated soil attributes and identify underlying soil quality factors. The frequency distributions of soil attributes comprising each factor were used to construct an index of soil quality for each factor. Four soil quality factors, termed the texture, organic matter, acidity, and phosphorus factors, were identified. Index scores for the organic matter and acidity factors varied significantly with land-use, but index scores for the texture factor did not vary significantly with land-use. Organic matter factor index scores were highest for native rangeland and perennial pasture, intermediate for land in CRP and wheat-row crop rotations, and lowest for wheat-fallow rotations. Wheat-fallow rotations also had significantly lower acidity factor index scores than native rangeland, perennial pastures, and land in CRP. Wheat-fallow rotations appear to be particularly detrimental to soil quality in the Central High Plains.